Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: nicksterrx7 on January 27, 2007, 05:48:38 PM

Title: Guess What I found when my engine was dismantled!!!!!!
Post by: nicksterrx7 on January 27, 2007, 05:48:38 PM
I\'ve been posting a fair bit recently as my car is in for a rebuild at the moment.

This post will be a simple statement of what we found when my engine was taken apart.  Not at all what I expected.

We knew that water was getting in somewhere and I was lucky enough to be permitted to watch as my engine was dismantled.

For information my car had a rebuild about 7 years ago by Hurley Engineering (their sports engine rebuild - with street porting).  The car has only done 40,000 in that time.  Here is what we found.

The exhaust ports had only really been polished (not widened to any degree)
Turbo 2 rotors (FC rather than FD) had been used in the rebuild
There was welding inside one of the rotor housings (the water seels didn\'t fit properly here)
There were multiple failures in water seels caused by deforming of the rotor housing (through wear)

Is it the norm to use FC rotors in FDs?  Is it the norm to refer to port polishing as \'porting\'?  Is it the norm to weld in pieces of metal to the rotor housing (where the water seals meet the rotor housing)?

Very interesting what you find when you take your engine to bits.  This is a simple statement of fact.  You pay your money and you takes your choice.
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: Warthog on January 27, 2007, 07:01:18 PM
Don\'t get me started again on that company.:Grrr

By the way who has pulled the engine. ?????
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: dubber91 on January 27, 2007, 07:28:45 PM
given that hurley sell their engines as \'sport\' engines, then does it really matter that the exhaust port has only been polished and not ported? So long as it still made the power they state when it came out the factory, the amount of work spent in that area doesnt really have too much affect in the larger scheme of things....does it.

I would never weld a rotor housing. Apart from the fact they are alloy (and thus can be a bastard to weld) but welding would lead to stress concentration points.........and thus the repeated warming up/cooling of the housing may lead to non uniform expansion accross the housing. This could lead to cracks propagating all over the place, and the potential of brittling of the housing. that its been done in the water seal area only goes to exacerbate the issue.

the \'wearing\' of the rotor housings.......is this wear on the polished (inside) face of the housing, or due to the expansion of the waterways? either way 7 years of use should not lead to the corrosion of this area. Likewise, 40000 should not be sufficient mileage with which to wear through to the water jacket on the other side. Either way might suggest non-new housings were used.

As for the rotors......it may not be normal, but if thats how hurley make the power, again, does it make a difference? I would sugest that they arent of better performance than the FD ones, but they may have an explaination for this.

Hope this helps. Ive tried to be impartial
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: Grizzly on January 27, 2007, 07:49:25 PM
I thought S5 T2 and S6 FD rotors where the same? (well very simalar)
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: John Yorke on January 27, 2007, 08:45:16 PM
Just trying to be positive - bearing in mind the engine \'ran\' for 7 years, all be it quite low miles over that time you must feel that you had a fair result compared to many on here.
The other thing, 7 years ago your options were limited as to where you could go and lets face it there was little or no tuning options for the FD3, I think it is great that we as a communitiy now have the experience and backround for these type of things not to happen now.
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: Timrxmotors on January 27, 2007, 09:52:24 PM
How do you know they are FC rotors,and not FD ones?
Some people do weld plates where the water seal sits,if it has broken,ok if done well,did the welding fail?
7 years is plenty long enough for corrosion to destroy a perfectly good engine if the coolant or cooling system aren\'t 100%.
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: dubber91 on January 27, 2007, 09:56:34 PM
yes but more scientifically, a weld introduces a stress point........I would never do it. IMHO
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: Timrxmotors on January 27, 2007, 10:03:15 PM
I have only ever welded one plate,that is in my 12A drag engine.No problems with the weld.
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: antnicuk on January 27, 2007, 11:29:52 PM
there are few things here:

first,  7 years is excellent for an FD rebuilt engine

40k miles is also excellent, not many people get that mileage on a rebuild.  see one of previous posts!

There is no difference between FD and FC rotors, so as tim\'s mentioned, not sure how they know the difference.

When you say the rotor housing has been welded.  Do you mean aliminium part?, people have used Turbo II ones which are the same except you need a hole welded up where the turbo II has a water way going to the inlet manifold. It was Common practice as the turbo II ones were a lot cheaper.   It obviously didnt effect performance.

If you mean one of the cast plates has been welded, its quite common and people have used chemical metal which again works well.  If the water jacket corrodes which is very common then its a cheap fix.  You dont what the original customer wanted to pay!

On a stock FD 7 years ago, polishing the exhaust port was about it, that way they could ensure that you didnt boost spike, also there were no ecu\'s available to tune more fuel for bigger ports!

All in all i dont see any wrong here at all!
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: kev-yorks on January 27, 2007, 11:38:03 PM
Think tony above has just about summed it up really:Thumbsup!
 
Kevin
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: antnicuk on January 27, 2007, 11:47:10 PM
Thanks Kev,  if i\'d known you were lerking, i would have waited and you could have typed that lot!
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: nicksterrx7 on January 28, 2007, 12:14:09 AM
I believe my statement was very measured, factual and unbiased.  You have all shared your views and I thank you for your thoughts.  As I said, you pays your money and you takes your choice.

The options now are greater, choice and competition are a good thing.  I\'ve had my FD long enough to have worked with many of the tuners and I know those I consider to offer good service and those that leave room for improvement.

Interesting views all.
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: kev-yorks on January 28, 2007, 07:05:28 AM
Quote from: nicksterrx7I believe my statement was very measured, factual and unbiased. You have all shared your views and I thank you for your thoughts. As I said, you pays your money and you takes your choice.
 
The options now are greater, choice and competition are a good thing. I\'ve had my FD long enough to have worked with many of the tuners and I know those I consider to offer good service and those that leave room for improvement.
 
Interesting views all.
Its nice to get a sensible thread on a engine rebuild autopsy well done all above. Thats the main thing Nick as you have realized we now have options in this country for building, porting and tuning that where not available to the degree they are now seven years ago plus no MRC to find out about these things. Some pics would be nice if you\'ve got them so we can see the wear and where you running 3mm seals as it is normal for excessive wear chatter marks with these, also what coolant was used (pink, blue or green) and how often was it changed as depending on type antifreeze breaks down and becomes acidic after a time actually eating away at the engine internally. Hence the recommendation to replace the coolant every two years.
 
Kevin:Thumbs-up
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: strange_days_uk on January 28, 2007, 07:49:03 AM
Quote from: antnicukthere are few things here:

first,  7 years is excellent for an FD rebuilt engine

40k miles is also excellent, not many people get that mileage on a rebuild.  see one of previous posts!

There is no difference between FD and FC rotors, so as tim\'s mentioned, not sure how they know the difference.

When you say the rotor housing has been welded.  Do you mean aliminium part?, people have used Turbo II ones which are the same except you need a hole welded up where the turbo II has a water way going to the inlet manifold. It was Common practice as the turbo II ones were a lot cheaper.   It obviously didnt effect performance.

If you mean one of the cast plates has been welded, its quite common and people have used chemical metal which again works well.  If the water jacket corrodes which is very common then its a cheap fix.  You dont what the original customer wanted to pay!

On a stock FD 7 years ago, polishing the exhaust port was about it, that way they could ensure that you didnt boost spike, also there were no ecu\'s available to tune more fuel for bigger ports!

All in all i dont see any wrong here at all!

Cheeers for the considered reply, good background and a balanced insight.

:guinness
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: Carl on January 28, 2007, 08:43:27 AM
There is a slight difference between FD and FC rotors.
If you are talking about the late FC turbo rotors,they are the same weight as FD rotors,but FD rotors are slightly,and I mean slightly more clearanced.

I think that 7 years is pretty good though,although the first post only mentions the "CARS" mileage,not the engines.

Regards
Carl
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: dubber91 on January 28, 2007, 08:58:53 AM
i think it depends upon the kind of rebuild that was done at hurleys. If i am honest, and I had paid top dollar for a top dollar rebuild then i might be unhappy with those findings.
Consider, for a second, that you pay £2000+ for a rebuild including New housings, a new rotor, new apex seals and gaskets. The only thing remaining that is second hand is the irons.
Personally i would not want to pay that sort of money for parts \'modified\' to fit, (some might say this modification may affect the longevity of the engine) and I would question why these parts were used instead of originals.
 On the other hand, if it was done cheaply, then 40000 miles from that engine using said \'modified\' parts, you really cant complain!
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: antnicuk on January 28, 2007, 05:04:25 PM
Quote from: dubber91i think it depends upon the kind of rebuild that was done at hurleys. If i am honest, and I had paid top dollar for a top dollar rebuild then i might be unhappy with those findings.
Consider, for a second, that you pay £2000+ for a rebuild including New housings, a new rotor, new apex seals and gaskets. The only thing remaining that is second hand is the irons.
Personally i would not want to pay that sort of money for parts \'modified\' to fit, (some might say this modification may affect the longevity of the engine) and I would question why these parts were used instead of originals.
 On the other hand, if it was done cheaply, then 40000 miles from that engine using said \'modified\' parts, you really cant complain!


for £2k you would get a very basic rebuild with all second hand parts exluding the seals and springs, I would estimate over 3k even 4K if you want new rotors with certain tuners!  

Carl,
I thought only very late FD rotors were clearenced the early ones are the same as FC,  seven years ago you wouldnt have been able to get hold of late FD rotors.

Nick
as kev mentioned, can you confirm what was welded and where?
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: dubber91 on January 28, 2007, 07:49:40 PM
not the sort of rebuilds i get done ;) anyways, thats a mere formallity, the point persists, top dollar rebuilds should not end up with modified parts and second hand parts.
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: antnicuk on January 28, 2007, 09:14:46 PM
who said it was a top dollar rebuild?
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: dubber91 on January 28, 2007, 09:37:47 PM
not me. Im just saying: you get what you pay for. If I paid top dollar i wouldnt want to find that upon rebuild.
If i paid £124.65 and a packet of chewing gum, then you cant really complain can you?

Steve
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: antnicuk on January 28, 2007, 10:54:15 PM
Quote from: dubber91not me. Im just saying: you get what you pay for. If I paid top dollar i wouldnt want to find that upon rebuild.
If i paid £124.65 and a packet of chewing gum, then you cant really complain can you?

Steve



very true,   unfortunately as people on here have recently found out, these practices are still going on though
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: Carl on January 29, 2007, 12:02:28 AM
Hi Tony,
FD rotors have been clearanced from day one,it was one of the minor changes over the FC engine.
I do know that during rebuilds some have put turbo 2 rotors into FD engines though.
Regards
Carl
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: nicksterrx7 on January 29, 2007, 07:40:39 AM
Just for info (not sure it\'s really relevant), I paid the \'going rate\' at the time for the rebuild - I don\'t believe it was a \'cheap\' deal.

I wish I\'d taken my camera at the weekend (didn\'t even take my phone with me).  If I have an opportunity I may try to get some snaps next week if the company who are rebuilding have no objections.  No guarantees.
Title: Guess What I found when my engine was dismantled!!!!!!
Post by: dubber91 on January 29, 2007, 08:53:06 AM
right. Get some pics mateo. I am intrigued about your findings